DENTON (UNT), Texas — New discoveries in the University of North Texas College of Science laboratory of Richard Dixon, Distinguished Research Professor of biological sciences and associate director of UNT’s BioDiscovery Institute, could help develop biomass crops better suited for processing into products such as aviation fuel, plastics and other industrial products.
Dixon and researchers Xin Wang, a visiting scientist, and postdoctoral fellow Chunliu Zhuo recently published their findings in Plant Cell, the nation’s top plant science journal. The research, in collaboration with Oakridge National Laboratory’s Center for Bioenergy Innovation, funded by the U.S. Department Energy, is part of the biotechnology industry’s goal to genetically modify crops to be more efficiently processed into these valuable products.
Their work involves lignin, the substance that makes plants woody and firm and helps them stand upright.
“Lignin is sort of the reinforced concrete in the plant cell wall,” Dixon said. “That’s why it’s in the tree in the first place — to protect it and help it to stand upright. But lignin is hard to biodegrade and break down into smaller molecules to convert to fuels.”
His lab has been working on creating plants with higher concentrations of C-lignin, a type of lignin found in seeds of certain exotic plants like vanilla orchids and certain species of cactus, which is simpler to process than lignin found in conventional biofuel crops due to its molecular structure.
If scientists could replace a big proportion of the normal lignin with C-lignin, it would also be easily separated and broken down into simple molecules for making plastics or polymers, rather than being burned or discarded. More efficient processing of lignin would make biofuels more profitable, increasing the viability of biofuels.
Dixon and fellow researchers envision plants such as switchgrass and poplar bioengineered to contain large concentrations of C-lignin and grown as crops that could be harvested and efficiently processed into alternatives to petroleum. Their new findings identify a class of enzymes that act the catalyst for joining up lignin units into C-lignin in plants. This knowledge will enable plant scientists to genetically modify crops with significant amounts of C-lignin.
Dixon hopes that, combined with alternative technologies for automobiles, renewable plant biomass eventually could completely replace petroleum.
“The ultimate dream would have a tree that’s engineered to be a factory taking sunlight and converting it into building blocks that can be diverted through technology to replace all the things that petroleum provides now,” Dixon said.
Wang, Zhuo and Dixon outlined their research findings in “Substrate-Specificity of LACCASE 8 Facilitates Polymerization of Caffeyl Alcohol for C-Lignin Biosynthesis in the Seed Coat of Cleome hassleriana” published online: https://doi.org/10.1105/tpc.20.00598.